Subdiaphragmatic Lymph Nodes Uptake on 18F-FDG PET/CT After COVID-19 Vaccination in the Thigh

Clin Nucl Med. 2022 Mar 1;47(3):275-276. doi: 10.1097/RLU.0000000000003941.


Since worldwide COVID-19 vaccination, 18F-FDG uptake in reactive axillary lymph nodes has been frequently observed in PET/CT studies. We describe a patient with breast cancer who underwent 18F-FDG PET/CT 7 days after receiving COVID-19 vaccination in the right thigh. 18F-FDG uptake was observed in nonenlarged right-sided inguinal, iliac, and para-aortic lymph nodes. As the thigh can be used as an alternate site for COVID-19 vaccine injection in case of lymphedema in both arms or for adequate axillary staging in patients with breast cancer, physicians should be aware of such 18F-FDG uptake pattern.

Publication types

  • Case Reports

MeSH terms

  • COVID-19 Vaccines*
  • COVID-19*
  • Fluorodeoxyglucose F18
  • Humans
  • Lymph Nodes / diagnostic imaging
  • Positron Emission Tomography Computed Tomography
  • SARS-CoV-2
  • Thigh / diagnostic imaging
  • Vaccination


  • COVID-19 Vaccines
  • Fluorodeoxyglucose F18